Motor vehicle transmissions, especially automatic transmissions, need at least one oil pump to deliver and build up the pressure of oil (ATF) in an oil circuit for the lubrication of gears and bearings, for the actuation of shift elements and/or for cooling the transmission. As main or primary pumps for the supply of oil to an automatic transmission, engine-driven, gear-type pumps or radial piston pumps are known. From DE 102 27 314 A1 by the Applicant, a so-termed converter neck pump is known, which is made as an internally geared pump (crescent moon pump) and is driven by the converter neck of the torque converter. In addition to such main pumps, secondary pumps are also used for automatic transmissions, and perform further oil supply functions instead of or in addition to the main pump. This may be the case, for example in vehicle with all-wheel or front-wheel drive as known from DE 202 12 093 U1 by the Applicant. In that case, in addition to the central transmission an auxiliary transmission which distributes an input torque from the central transmission to the front and rear axles has to be supplied with oil. In the publication “Six-gear automatic transmission and all-wheel drive” by Henning and Magnussen in ATZ, July 2002, Special Edition VW Phaeton, pp. 60 to 66, a secondary oil pump of this type for an auxiliary transmission id disclosed. The oil pump is an internally geared pump, has a pump housing bolted onto a transmission housing and is driven by a so-termed cross-shaft of the transmission. The cross shaft itself is driven by a gear, spur gear or so-termed beveloid gearing stage. This the spur gear is overhang-mounted on the cross shaft. For optimum meshing of the gear stage such overhang mounting is unsuitable, inasmuch as bending deflection and tilting at the gear meshing point can have negative results in relation to gear noise and lifetime. Moreover, it is also a disadvantage that because of the bending of the spur gear shaft (cross shaft) relatively large play is needed in the drive connection between the spur gear shaft and the pump drive shaft, which results in a corresponding increase in noise and a more rapid wear.
Starting from the above prior art, the purpose of the present invention is to provide for a device of the type mentioned above with an improved pump drive system, which operates with little generated noise and which has a longer life.